000
FXUS63 KLSX 250453
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1054 PM CST TUE NOV 24 2009

.DISCUSSION...
/306 PM CST TUE NOV 24 2009/

THE UPPER LOW CURRENTLY CENTERED OVER THE CENTRAL MO/IA BORDER
WILL CONTINUE TO MOVE ENEWD TONIGHT AND INTO THE LOWER GREAT LAKES
BY DAYBREAK IN RESPONSE TO THE DIGG UPSTREAM TROF NOW IN ALBERTA.
THE ASSOCIATED COLD FRONT WILL EXIT THE CWA INTO ERN IL BY EARLY
EVENING ALONG WITH THE PREFRONTAL BAND OF RAIN. SO FOR MOST OF
TONIGHT...THE MAIN STORY WILL BE GUSTY WNW WINDS AND COOLING
TEMPERATURES WITH A CHANCE OF SOME LIGHT RAIN ACROSS MAINLY NE MO
AND WEST CENTRAL IL IN THE CYCLONIC FLOW ABOUT THE EXITING LOW.
THE ANTICIPATED SECOND STRONGER COLD FRONT WILL COME RACING ACROSS
THE AREA ON WEDNESDAY AS THE UPSTREAM TROF/UPR LOW DIGS INTO SE IA
BY EARLY EVENING. THIS FRONT WILL ALSO BE ACCOMPANIED BY GUSTY NW
WINDS AND A LOW CHANCE OF SOME LIGHT RAIN/SNOW ON WEDNESDAY NIGHT
ACROSS NE MO INTO CENTRAL IL AS A SPOKE OF VORTICITY ROTATES SEWD
THRU THE AREA. THANKSGIVING DAY CONTINUES TO LOOK LIKE THE COLDEST
DAY THUS FAR THIS FALL WITH MOSTLY CLOUDY AND BLUSTERY CONDITIONS.
THERE COULD ALSO BE SOME SPRINKLES/FLURRIES WITHIN THE DEEP
CYCLONIC FLOW ACROSS THE NE HALF OF THE AREA.

DESPITE THE DEPTH OF THIS TROF AS IT DIGS TO OUR EAST INTO THE OH
VLY ON THURSDAY IT REMAINS PROGRESSIVE AND BY FRIDAY HEIGHTS ALOFT
ARE ALREADY ON THE RISE THROUGH THE MS VLY. THE WEAK SFC RIDGE
WILL ALSO BE DEPARTING WITH SLY WINDS AND WAA RETURNING...AND A
GOOD REBOUND IN TEMPERATURES. TEMPERATURES WILL CONTINUE TO WARM
INTO SATURDAY AS SWLY FLOW BECOMES ESTABLISHED AND UPPER LEVEL
RIDGING PROGRESSES FROM THE MS INTO THE OH VLY. WITH H85 TEMPS AOA
+10 DEGC FORCAST I HAVE GONE ABOVE ALL OF THE GUIDANCE...AND STILL
COULD BE A GOOD 5 TO 10 DEGS TOO COOL ON MY HIGHS SAT.

CONFIDENCE IN THE FORECAST ALONG WITH DETAILS LOWERS SIGNIFICANTLY
FROM SUNDAY INTO THE FIRST PART OF NEXT WEEK. THERE IS CONSIDERABLE
SPREAD IN THE DETERMINISTIC MODELS AND THE ENSEMBLE MEMBERS.
SPAGHETTI PLOTS LOOK JUST LIKE SPAGHETTI. THE COMMON THEME IS A NEW
TROF MOVING FROM THE WRN INTO THE CENTRAL U.S. AND AN ASSOCIATED
COLD FROPA...HOWEVER THERE IS ALOT OF VARIANCE IN THE NORTHERN AND
SOUTHERN STREAMS/PHASING AND ASSOCIATED IMPACTS. AT THIS POINT IT
SEEMS FAIR TO SAY THAT THE PCPN CHANCES APPEAR TO BE INCREASING IN
THE SUNDAY NIGHT INTO TUESDAY TIME FRAME...AND ACCORDINGLY I HAVE
INTRODUCED SOME MENTIONABLE POPS INTO THE FCST.

GLASS
&&

.AVIATION...
/1054 PM CST TUE NOV 24 2009/

FOR THE 06Z TAFS...MAIN ISSUE CONTINUES TO BE MVFR CIGS FOR MAJORITY
OF FORECAST PERIOD. AT KUIN...CIGS HAVE DIPPED DOWN TO IFR...WHILE
REST OF SITES TO REMAIN MVFR. AS SYSTEM MOVES FURTHER AWAY FROM TAF
SITES SHOULD SEE SOME BREAKS IN THE CIGS BY MID TO LATE MORNING
...THEN ANOTHER SHORTWAVE APPROACHES BRINGING MVFR DECK BACK IN
BETWEEN 20Z AND 23Z. GUSTY WEST TO NORTHWEST WINDS TO PERSIST.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$
WFO LSX